Inch by inch, EUVL is moving forward. The big problem is that it has
not moved forward fast enough to be inserted confidently into any given
future technology node. Although news from SEMATECH today touts
‘production-enabling breakthroughs’ being presented at the 2007
International EUVL Symposium, the press release lacks any mention of
the timing for EUVL entering production!

This has become a recurring theme in 2007 as EUVL was pushed out at
the 32nm node at the SPIE Lithography conference in February this year,
and no one has yet been brave enough to re-insert it at any future node
with any conviction.

That aside, SEMATECH has listed the
‘breakthroughs,’ so we will have to see if this makes any difference to
putting a ‘date’ on EUVL entering fabs.

Below is a sample of advances as revealed by SEMATECH technologists in papers that are being delivered at the symposium:

The best EUV mask blank defect density in the world today – 0.1 per cm2 at
56nm resolution – will be reported by Chan-Uk Jeon, program manager of
the Mask Blank Development Center in Albany, NY. SEMATECH also has
created a detailed database of the source of the defects and is
developing mitigation methods, such as smoothing, to reduce pit
defects. (This SEMATECH smoothing process has achieved an 800X
improvement in defect levels.) SEMATECH’s work will likely enable mask
blanks to be ready for EUV beta tools in 2009.

SEMATECH
has achieved only five added defects at 56nm sensitivity in EUV mask
blank defect totals, according to a paper by Patrick Kearney, Member
Technical Staff. This milestone was enabled with industry-leading 56nm
defect inspection sensitivity on multilayer coated blanks, and is
rooted in SEMATECH’s strategy of collaborating with suppliers to bring
together all elements of the industry.

A
manufacturable EUVL reticle solution also requires defect-free reticle
handling. EUVL reticle protection using SEMATECH’s “sPod” design shows
an average of less than one particle added per 100 separate reticle
transfers, as explained in a paper by Long He, project engineer. Tests
also show the sPod as a potential solution for shipping and storage.

Using
the industry’s best EUV resist exposure capability, SEMATECH has
demonstrated that effective resolution down to 24nm can be achieved
with current resists and optimized illumination conditions. These
results are documented by Andy Ma, EUV resist bench project manager. Ma
also describes remaining resist challenges, including linewidth
roughness and photospeed.

Current optical designs
for EUV collectors are not very efficient, but SEMATECH has developed a
series of upgrades that could boost collector efficiency by 2.8X. That
would reduce the industry’s critical dependence on high-power sources
or improve tool throughput and cost effectiveness. The designs are
explained in a paper by Michael Goldstein, Senior Technologist.

Detailed
cost-of-ownership targets for EUVL – as determined by SEMATECH’s
detailed cost models – will be reported by Phil Seidel, Senior Member
Technical Staff. These performance targets have been integrated into
the consortium’s technology development projects, and show that the key
elements for cost effective EUVL include source power, optics lifetime,
and mask blank defect reduction.